Currently in the United States there are 360,000 small vessel implants and 100,000 peripheral vascular reconstructions annually. Of this population needing vascular surgery, approximately 15% of the patients do not have vessels suitable for autografts. A prototype procedure has been developed for the cryogenic preservation of arteries and veins with an intact endothelia lining for transplantation. This proposal is for completion of the development of cryogenic technology along with ancillary surgical and transport methodologies to enable the commercialization of arterial and venous homografts for the medical community. In the phase 1 portion of this grant optimization of the cryobiological procedures and testing of the efficacy of vessels stored using this proprietary technology will be performed in a canine model system. Efficacy of he preservation will be judged by the integrity of the endothelium using morphological criteria, patency, factor VIII staining, adhesion of radio-labelled platelets, in vitro proliferative capacity and prostacyclin production. Commercialization will be similar to CryoLife's current procedure on aortic and pulmonary valve conduits. Specifically, the organ procurement agencies or other sources will send tissue to CryoLife where the tissue will be typed, sterilized and frozen. The frozen tissue will then be returned to the originating hospital and stored in a liquid nitrogen freezer until needed by a suitable recipient.